System and method for identifying objects using capacitive sensing technology

ABSTRACT

Embodiments disclosed herein provide for an improved system and method of identifying objects using capacitive sensing technology. Embodiments provide for a sensing array including a plurality of capacitive sensor pads, as well as a microcontroller configured to detect and identify the plurality of objects. Embodiments further provide for encoding each of the plurality of objects with a unique ternary code.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 16/005,350, filed on Jun. 11, 2018, the disclosure of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present application relates to an improved system and method ofidentifying objects using capacitive sensing technology.

BACKGROUND

Capacitive sensing relies on the electrical concept of a parallel-platecapacitor, where the total capacitance is dependent on (i) the area ofthe two parallel plates, (ii) the distance between the two parallelplates, and (iii) the dielectric constant of the material in between thetwo plates, e.g.,

$C = {\frac{ɛ_{r}}{d}{A.}}$In many capacitive sensing applications, the human body forms one plateof the capacitor referenced to a virtual ground. Capacitive sensing istypically used to detect the presence of a human finger (or fingers)and, based on this detection, cause some action to take place. In itssimplest form, the capacitive sensor replaces a mechanical switch, thuseliminating the failures typical of mechanical devices and providing amore design-friendly user interface for a product. Capacitive sensingcan also be used in industrial applications as proximity detectors,e.g., to sense the presence or absence of an object on a conveyor belt.However, capacitive sensing technologies do not generally provide objectrecognition and identification capabilities. Instead, if a designerrequires a non-contact and non-mechanical method of uniquely identifyingan object, other technologies such as radiofrequency identification(RFID), near-field communication (NFC), optical scanning (e.g., barcodes, QR codes, etc.), or image recognition are utilized. Suchtechnologies are generally cost-prohibitive and are therefore notutilized in most toy applications.

Accordingly, there is a need for a low-cost method of identifyingmultiple objects placed on the surface of a toy that does not require anelectro-mechanical interface (e.g., physical switch or switches).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example embodiment of a capacitive sensing system.

FIG. 2A illustrates an embodiment of the capacitive sensing arraydepicted in FIG. 1.

FIG. 2B illustrates an embodiment of an object to be sensed by thecapacitive sensing system in FIG. 1.

FIG. 2C illustrates another embodiment of the object depicted in FIG.2B.

FIG. 2D illustrates embodiments of the conductive surfaces depicted inFIGS. 2B and 2C.

FIG. 3 illustrates possible ternary codes and corresponding decimalequivalents for the objects depicted in FIGS. 2B and 2C.

FIG. 4 illustrates an example embodiment of a method utilized toidentify the objects depicted in FIGS. 2B and 2C.

DESCRIPTION OF EMBODIMENTS

The following description of embodiments provides non-limitingrepresentative examples referencing numerals to particularly describefeatures and teachings of different aspects of the invention. Theembodiments described should be recognized as capable of implementationseparately, or in combination, with other embodiments from thedescription of the embodiments. A person of ordinary skill in the artreviewing the description of embodiments should be able to learn andunderstand the different described aspects of the invention. Thedescription of embodiments should facilitate understanding of theinvention to such an extent that other implementations, not specificallycovered but within the knowledge of a person of skill in the art havingread the description of embodiments, would be understood to beconsistent with an application of the invention.

One aspect of the present disclosure is to provide an improved systemand method of identifying objects using capacitive sensing technology.The methods herein address at least one of the problems discussed above.

According to an embodiment, a system for identifying a plurality ofobjects using capacitive sensing includes (i) a sensing array, wherein:the sensing array includes a plurality of capacitive sensor pads; andeach of the plurality of objects includes at least one conductivesurface, the at least one conductive surface being configured to form atleast one capacitance with at least one of the plurality of capacitivesensor pads; and (ii) a microcontroller, wherein the microcontroller isconfigured to (a) detect the at least one capacitance between each ofthe plurality of objects and the plurality of capacitive sensor pads and(b) identify each of the plurality of objects based on the detected atleast one capacitance, wherein each of the plurality of objects areidentified with a ternary code.

According to an embodiment, a method for identifying a plurality ofobjects using capacitive sensing includes forming at least onecapacitance between at least one conductive surface of one of theplurality of objects and at least one of a plurality of capacitivesensor pads of a sensing array; detecting, with a microcontroller, theat least one capacitance between the one of the plurality of objects andthe plurality of capacitive sensor pads; and identifying, with themicrocontroller, the one of the plurality of objects based on thedetected at least one capacitance, wherein the one of the plurality ofobjects is identified with a ternary code.

FIG. 1 illustrates an example embodiment of a capacitive sensing system.As depicted in the figure, a capacitive sensing system 100 includes acapacitive sensing array 10, a microcontroller system 20, a userinterface 30, display/status electronics 40, power supply 50, and awireless communication subsystem 60. In an embodiment, the capacitivesensing array 10 includes a plurality of capacitive sensor pads CS. Forexample, the capacitive sensing array 10 includes capacitive sensor padsCS0 to CSn. In an embodiment, the microcontroller subsystem 20 mayinclude either a 16 bit or 32 bit microcontroller. Further, themicrocontroller includes software libraries for capacitive sensing thatenable access to raw capacitance data, sensor calibration and baselineroutines, scanning routines, and sensitivity adjustment routines. In anembodiment, the user interface 30 may include buttons, switches and/orkeypads in order to accept user input. Further, the user interface 30may also include a loudspeaker or transducer in order to provide audiblefeedback. In an embodiment, the display/status electronics 40 mayinclude an active display such as a liquid-crystal display (LCD) or anorganic light-emitting diode (OLED). Further, in an embodiment, theactive display may be color or monochrome. In another embodiment, thedisplay/status electronics 40 may also include light-emitting diode(LED) indicators. In an embodiment, the display/status electronics 40may display information to the user based on the user's interaction withthe user interface 30. In an embodiment, the power supply 50 may be abattery based on dry cells. In another embodiment, the power supply 50may be a rechargeable battery, e.g., lithium ion (Li-ion). In anembodiment, the wireless communication subsystem 60 may be a wirelesscommunication based on Bluetooth low energy (BLE), WiFi, infrared (IR),or similar protocols. In an embodiment, the wireless communicationsubsystem 60 may be used to connect the capacitive sensing system 100 toanother device, e.g., computer, mobile phone, etc. For example, thewireless communication subsystem 60 may be used to control a roboticdevice based on the identification of the plurality of objects.

FIG. 2A illustrates an embodiment of the capacitive sensing arraydepicted in FIG. 1. In an embodiment, as depicted in the figure, thecapacitive sensing array 10 includes a ground plane 10 a and a pluralityof capacitive sensor pads CS. The capacitive sensing array may alsoinclude a printed circuit board (PCB) (not shown). In an embodiment, thePCB is a non-conductive (i.e., insulating) substrate material. Further,the capacitive sensor pads CS are constructed on the PCB usingconductive material. In an embodiment, the conductive material could becopper tape, pads on the PCB material, metal plates, conductive plastic,conductive paint, etc. Further, as depicted in the figure, thecapacitive sensor pads CS each have a circular shape, thereby providinguniform capacitance values. However, in another embodiment, thecapacitive sensor pads CS can also be square-shaped. In an embodiment,the dimensions of the capacitive sensor pads CS depend on a plurality offactors such as the physical size of the object to be identified as wellas the number of capacitive sensor pads CS required. Further, as thearea of the capacitive sensor pads CS decreases, so does thecapacitance. Further, the capacitive sensor pads CS are connected to themicrocontroller subsystem 20. However, traces (not shown) from thecapacitive sensors pads CS to the microcontroller subsystem 20 are keptto a minimum to reduce the effect of the trace on the capacitivesensing. Further, the area of the capacitive sensor pad CS must be largewhen compared to the trace width. In addition, the arrangement of thecapacitive sensor pads CS may be in any pattern or orientation thatserves the intended purpose. For example, a rectangular object might bebest served by having sensor pads arranged in a straight line, whereas asquare object might require sensor pads in each corner. For instance,the arrangement of the capacitive sensor pads CS in FIG. 2A assumes thatthe object to be sensed is rectangular. As such, each object will beassociated with four horizontally adjacent sensors arranged in astraight line. However, this number can be reduced or expanded asrequired. Further, sensors must be shielded from stray noise through useof a ground plane on both sides of the printed circuit board (e.g., theground plane 10 a); the ground plane may either be solid or hatched. Forexample, the ground plane 10 a is hatched. Further, the ground plane 10a may be comprised of a conductive material, e.g., copper. In anembodiment, the ground plane 10 a is located in a plane adjacent to thecapacitive sensor pads CS and, therefore, surrounds the capacitivesensor pads CS. Further, as depicted in the figure, there may be aclearance between the capacitive sensor pads CS and the ground plane 10a.

FIG. 2B illustrates an embodiment of an object to be sensed by thecapacitive sensing system in FIG. 1. As depicted in the figure, object70 is block-shaped and includes a plurality of conductive surfaces 71.In an embodiment, each of the capacitive sensor pads CS may beassociated with a corresponding conductive surface 71. In an embodiment,similar to the conductive material for the capacitive sensors CS, theplurality of conductive surfaces 71 may be one of copper tape, pads onPCB material, metal plates, conductive plastic, conductive paint, etc.As such, a capacitance may form between a particular capacitive sensorpad CS and a corresponding conductive surface 71. However, a capacitivesensor pad CS need not be associated with any conductive surface 71. Inthis case, no capacitance would form with the capacitive sensor pad CS.Accordingly, based on whether a capacitance forms with the capacitivesensor pad CS, it can be determined if a conductive surface 71 islocated across from the particular capacitive sensor pad CS.

In an embodiment, the conductive surfaces 71 are mounted on an outsidesurface of the object, e.g., on a bottom surface of the object 70.Further, in an embodiment, the body of the object 70 is hollow. Inanother embodiment, the body of the object 70 may be solid. Further, theobject 70 may include conductive surfaces 71 of different sizes. Forexample, the conductive surfaces 71 may have a surface area that iseither larger or smaller than the surface area of a correspondingcapacitive sensors CS. For example, in an embodiment, the surface areaof the larger conductive surface 71 may be three times the size of thesmaller conductive surface 71. In an embodiment, a conductive surface 71with a larger surface area forms a larger capacitance with acorresponding capacitive sensor pad CS than a capacitance with a smallersurface area. For example, the conductive surface 71 with a largersurface area may form a capacitance that is three times larger than theconductive surface 71 with a smaller surface area. As such, based on thecapacitance between the particular conductive surface 71 and thecorresponding capacitive sensor pads CS, it can be determined which ofthe larger or smaller conductive surfaces 71 is being utilized.

In addition, FIG. 2B also depicts the ground plane 10 a, a printedcircuit board (PCB) 10 b, and a device surface 10 c. As described above,the PCB 10 b is a non-conductive (i.e., insulating) substrate material.Further, the capacitive sensor pads CS are constructed on the PCB 10 busing conductive material. Further, in an embodiment, the device surface10 c is a plastic layer enclosing the system 100. The plastic layer canbe one of the variety of plastics used in children's toys. For example,the plastic may be one of acrylonitrile butadiene styrene (ABS) orpolypropylene (PP).

FIG. 2C illustrates another embodiment of the object depicted in FIG.2B. In particular, unlike FIG. 2B, in which the conductive surfaces 71are mounted on the outside of the object 70, the conductive surfaces 71in FIG. 2C are mounted in the inside of the object 70, e.g., the bottominside surface of the object 70.

FIG. 2D illustrates embodiments of the conductive surfaces depicted inFIGS. 2B and 2C. In an embodiment, conductive surface 71 a has a surfacearea smaller than the capacitive sensor CS, while conductive surface 71b has a surface area larger than the capacitive sensor CS.

In an embodiment, an object 70 can be identified by the system 100 basedon the particular capacitances associated with each of the capacitivesensor pads CS. In an embodiment, each capacitive sensor pad CS can beassociated with one of the three capacitance ranges: (i) capacitanceassociated with the conductive surface 71 a (e.g., small surface area),(ii) capacitance associated with the conductive surface 71 b (e.g.,large surface area), and (iii) capacitance associated with no conductivesurface 71. As such, utilizing the quantity and sizes of the conductivesurfaces 71, as well as the location of the conductive surfaces 71 (andany locations parallel to a corresponding capacitive sensor withoutconductive surfaces 71), the object 70 can be uniquely encoded with aparticular identification (ID). In particular, in an embodiment, becauseeach of the capacitive sensor pads CS can be associated with threecapacitive ranges, each of the objects 70 can be encoded utilizingternary encoding. In an embodiment, unlike binary, which establishes twolevels—zero and one—for each binary digit or “bit”, ternary encodes eachternary digit, or “trit” with three levels—zero, one or two. The maximumnumber of possible codes for a given number of trits is given by 3^(n),and the highest decimal value is 3^(n) ⁻¹ . Thus, with two trits (i.e.,two capacitive sensor pads CS), nine potential codes are possible withthe highest code value being eight. In comparison, two binary digitswould only encode 2^(n) values or four codes. As such, four capacitivesensor pads CS (as depicted in FIG. 2A), each object 70 can be encodedwith four trits, with each trit being given a level of 0, 1, or 2.Accordingly, the total number of object codes possible is 81, with thehighest value being 80. In an embodiment, the objects 70 can be encodedfrom left to right. In other words, the leftmost capacitive sensors padsCS in the capacitive sensor array 10 of FIG. 2A are associated with theleast significant trit positions (e.g., trit 0), while the rightmostcapacitive sensor pads CS are associated with the most significant tritpositions (e.g., trit 3). However, in another embodiment, the encodingcan be reversed, i.e., leftmost capacitive sensors pads CS areassociated with the most significant trit positions (e.g., trit 3),while the rightmost capacitive sensor pads CS are associated with theleast significant trit positions (e.g., trit 0). In an embodiment, ifthe least significant trit position, e.g., trit 0, does not include anyconductive surfaces 71, then trit 0 will be given a level of 0. On theother hand, if trit 0 includes a conductive surface 71 having thesmaller surface area, e.g., conductive surface 71 a, then trit 0 will begiven a level of 1. However, if trit 0 includes a conductive surfacehaving the larger surface area, e.g., conductive surface 71 b, then trit0 will be given a level of 2. Then, based on the level (e.g., 0, 1, or2) associated with each trit, a decimal equivalent can be determined.Specially, the decimal equivalent of trit is added together to determinea combined decimal equivalent. For example, the decimal equivalent fortrit 0=(level₀)×3°. As such, if the level for trit 0 is 0, then thedecimal equivalent will also be 0. However, if the level for trit 0 is1, then the decimal equivalent will also be 1. Similarly, if the levelfor trit 0 is 2, then the decimal equivalent will also be 2. As regardsto trit 1, the decimal equivalent=(level₁)×3¹. As such, if the level fortrit 1 is 0, then the decimal equivalent will also be 0. However, if thelevel for trit 1 is 1, then the decimal equivalent will be 3. Similarly,if the level for trit 1 is 2, then the decimal equivalent will also be6. As regards to trit 2, the decimal equivalent=(level₂)×3². As such, ifthe level for trit 2 is 0, then the decimal equivalent will also be 0.However, if the level for trit 2 is 1, then the decimal equivalent willbe 9. Similarly, if the level for trit 2 is 2, then the decimalequivalent will be 18. Further, as regards to trit 3, the decimalequivalent=(level₃)×3³. As such, if the level for trit 3 is 0, then thedecimal equivalent will also be 0. However, if the level for trit 3 is1, then the decimal equivalent will be 27. Similarly, if the level fortrit 3 is 2, then the decimal equivalent will be 54. Accordingly, thedecimal equivalent for any object

$70 = {{\left( {level}_{3} \right) \times 3^{3}} + {\left( {level}_{2} \right) \times 3^{2}} + {\left( {level}_{1} \right) \times 3^{1}} + {\left( {level}_{0} \right) \times 3^{0}\mspace{14mu}{or}\mspace{14mu}{\sum\limits_{1}^{n}{\left( {level}_{n - 1} \right){3^{n - 1}.}}}}}$FIG. 3 illustrates the possible ternary codes and corresponding decimalequivalents for the object 70. For example, the object 70 in FIGS. 2Band 2C, which includes, from left to right, a conductive surface 71 a, aconductive surface 71 b, a conductive surface 71 a, and a conductivesurface 71 b, respectively, would have a corresponding ternary code of1212 and, therefore, a decimal equivalent of 50 (i.e.,(1)×3³+(2)×3²+(1)×3¹+(2)×3⁰). Further, in an embodiment, the ternarycodes can be utilized for a variety of different-numbered sensorapplications. For example, as depicted in FIG. 3, the ternary codesassociated with the decimal equivalents 0 to 8, respectively, can beutilized for two-sensor applications. Further, the ternary codesassociated with the decimal equivalents 9 to 26, respectively, can beutilized for three-sensor applications. Lastly, the ternary codesassociated with the decimal equivalents 27 to 80, respectively, can beutilized for four-sensor applications. In an embodiment, the number oftrits used can be expanded or reduced depending on the number ofcapacitive sensor pads CS utilized.

FIG. 4 illustrates an example embodiment of a method utilized toidentify the objects depicted in FIGS. 2B and 2C. In a first step, i.e.,step 200, the system 100 is powered, e.g., via the power supply 50. Inan embodiment, the system 100 may be powered by interacting (e.g.,switching on) a power button located at the user interface 30. Further,in an embodiment, after the system 100 is powered, calibration signals(e.g., voltage signals) can be provided from the microcontrollersubsystem 20 to the capacitive sensor pads CS in the sensing array 10.As such, the microcontroller subsystem 20 can then calibrate the basecount capacitance for each of the capacitive sensor pads CS as depictedin step 201. For example, the microcontroller subsystem 20 can calibratethe capacitive sensors pads CS associated with trit 0, trit 1, trit 2,and trit 3, respectively. The calibrated base count capacitances for thecapacitive sensors pads CS may then be stored in the microcontrollersubsystem 20 for further processing. Then, in step 203, the system 100waits until a user initiates the sensing operation, i.e., by pressing astart key/button. In an embodiment, the start key/button may also belocated in the user interface 30. In an embodiment, if the startkey/button is pressed, the ID associated with the object 70 (e.g.,BlockID) is reset to zero as depicted in step 203. In an embodiment, theBlockID for a particular object 70 may be stored in a memory located atthe microcontroller subsystem 20. Further, the microcontroller subsystemmay also declare (and then store) the upper and lower capacitance limitsassociated with the larger and smaller conductive surfaces 71, e.g.,UpperLimit and LowerLimit, respectively. For example, UpperLimit may beassociated with the larger conductive surface 71 (i.e., 71 b)capacitance and the LowerLimit may be associated with the smallerconductive surface 71 (i.e., 71 a) capacitance. Further, in anembodiment, the UpperLimit capacitance may be three times larger thanthe LowerLimit capacitance. Then, the microcontroller subsystem 20 mayread the raw capacitance data at the capacitive sensors pads CSassociated with trit 0, trit 1, trit 2, and trit 3, e.g., Rawdata0,Rawdata1, Rawdata2, and Rawdata3, respectively. Then, as depicted instep 204, the microcontroller subsystem 20 may calculate the capacitancedifference (i.e., delta values Delta0, Delta1, Delta 2, and Delta3)between the received raw data (e.g., Rawdata0, Rawdata1, Rawdata2,Rawdata3) and the base count (e.g., BaseCount0, BaseCount1, BaseCount2,BaseCount3) for each capacitive sensor pad CS. Then, as depicted insteps 205 to 228, the microcontroller compares the delta value at eachcapacitive sensor pad CS to the UpperLimit and LowerLimit to determinethe decimal equivalent (e.g., ternary weight) of the trit associated theparticular capacitive sensor pad CS. For example, as depicted in step205, the microcontroller subsystem 20 compares Delta0 (i.e.,Rawdata0-BaseCount0) to UpperLimit. If it is determined that Delta0 isgreater than UpperLimit, than the BlockId for that particular object isincremented by 2 (i.e., BlockID=BlockID+2) as depicted in step 206.However, if Delta0 is not greater than the UpperLimit, then the methodproceeds to step 207, where Delta0 is compared to LowerLimit as well. Ifit is determined that Delta0 is less than UpperLimit but greater thanLowerLimit, then the BlockId for that particular object is incrementedby 1 (i.e., BlockID=BlockID+1) as depicted in step 208. However, ifDelta® is less than UpperLimit and LowerLimit, then Delta0 is set to “0”as depicted in step 209 and, therefore, BlockID will not be incremented.Accordingly, as depicted in step 201, the decimal equivalent at thecapacitive sensor pad CS associated with the least significant trit(i.e., CS0) is determined and, therefore, can be stored in the memoryfor further processing. Then, in step 211, the microcontroller subsystem20 compares Delta1 (i.e., Rawdata1-BaseCount1) to UpperLimit. If it isdetermined that Delta1 is greater than UpperLimit, than the BlockId forthat particular object is incremented by 6 (i.e., BlockID=BlockID+6) asdepicted in step 212. However, if Delta1 is not greater than theUpperLimit, then the method proceeds to step 213, where Delta0 iscompared to LowerLimit as well. If it is determined that Delta1 is lessthan UpperLimit but greater than LowerLimit, then the BlockId for thatparticular object is incremented by 3 (i.e., BlockID=BlockID+3) asdepicted in step 214. However, if Delta1 is less than UpperLimit andLowerLimit, then Delta1 is set to “0” as depicted in step 215 and,therefore, BlockID will not be incremented. Accordingly, as depicted instep 216, the decimal equivalent at the capacitive sensor pad CSassociated with the second least significant trit (i.e., CS1) isdetermined and, therefore, can be stored in the memory for furtherprocessing. Then, in step 217, the microcontroller subsystem 20 comparesDelta2 (i.e., Rawdata2-BaseCount2) to UpperLimit. If it is determinedthat Delta2 is greater than UpperLimit, than the BlockId for thatparticular object is incremented by 18 (i.e., BlockID=BlockID+18) asdepicted in step 218. However, if Delta2 is not greater than theUpperLimit, then the method proceeds to step 219, where Delta2 iscompared to LowerLimit as well. If it is determined that Delta2 is lessthan UpperLimit but greater than LowerLimit, then the BlockId for thatparticular object is incremented by 9 (i.e., BlockID=BlockID+9) asdepicted in step 220. However, if Delta2 is less than UpperLimit andLowerLimit, then Delta2 is set to “0” as depicted in step 221 and,therefore, BlockID will not be incremented. Accordingly, as depicted instep 222, the decimal equivalent at the capacitive sensor pad CSassociated with the second most significant trit (i.e., CS2) isdetermined and, therefore, can be stored in the memory for furtherprocessing. Then, in step 223, the microcontroller subsystem 20 comparesDelta3 (i.e., Rawdata3-BaseCount3) to UpperLimit. If it is determinedthat Delta3 is greater than UpperLimit, than the BlockId for thatparticular object is incremented by 54 (i.e., BlockID=BlockID+18) asdepicted in step 224. However, if Delta3 is not greater than theUpperLimit, then the method proceeds to step 225, where Delta3 iscompared to LowerLimit as well. If it is determined that Delta3 is lessthan UpperLimit but greater than LowerLimit, then the BlockId for thatparticular object is incremented by 27 (i.e., BlockID=BlockID+27) asdepicted in step 226. However, if Delta3 is less than UpperLimit andLowerLimit, then Delta3 is set to “0” as depicted in step 227 and,therefore, BlockID will not be incremented. Accordingly, as depicted instep 228, the decimal equivalent at the capacitive sensor pad CSassociated with the most significant trit (i.e., CS3) is determined and,therefore, can be stored in the memory for further processing. In anembodiment, as depicted in step 229, the BlockID value is thendetermined by adding the values stored for CS0, CS1, CS2, and CS3. In anembodiment, the decimal equivalent for each of CS0, CS1, CS2, and CS3 isdetermined sequentially. However, in another embodiment, the decimalequivalent for each of CS0, CS1, CS2, and CS3 can be determinedsimultaneously. Further, in an embodiment, the system 100 can use theabove method to identify a plurality of objects 70. For example, theabove method can be used to identify a second object with capacitivesensors CS4, CS5, CS6, CS7. Similarly, a nth object can be identifiedwith capacitive sensors CSn-3, CSn-2, CSn-1, and CSn. Further, in anembodiment, the plurality of objects can either be detected sequentiallyor simultaneously.

In an embodiment, after identifying each of the plurality of objects,the microcontroller subsystem 20 can determine if the plurality ofobjects are placed in the correct sequential order by comparing theplacement of the plurality of objects 70 to a preferred placement. Forexample, the preferred placement may require that: a first block isplaced over the area including capacitive sensors CS0 to CS3, a secondblock is placed over the area including capacitive sensors CS4 to CS7, .. . and a nth block is placed over the area including CSn-3 to CSn. Inan embodiment, the preferred placement may be stored in memory in themicrocontroller subsystem 20. In an embodiment, the system 100 mayindicate correct or incorrect placement of the objects 70 throughaudible feedback at the user interface, e.g., via the loudspeaker ortransducer. For example, if after the comparison, it is determined thatthe placement was correct, the loudspeaker or transducer may produce anoise indicating approval. On the other hand, if after the comparison,it is determined that the placement was incorrect, the loudspeaker ortransducer may produce a noise indicating disapproval. In anotherembodiment, approval and/or disapproval may also be indicated with thedisplay/status electronics 40. For example, approval may be indicated byflashing the LED indicators with a first color (e.g., green) anddisapproval may be indicated by flashing the LED indicators with asecond color (e.g., red). Further, in another embodiment, the approvaland/or disapproval may be indicated by a message (e.g., “CORRECT,”“WRONG,” etc.) appearing on the active display.

Further, in an embodiment, after it is determined that the placement wascorrect, the system 100 can transmit, via the wireless communicationsubsystem 60, instructions from the microcontroller subsystem 20 toanother device. In an embodiment, the other device may be a roboticdevice, e.g., toy.

In the foregoing Description of Embodiments, various features may begrouped together in a single embodiment for purposes of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claims require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive aspects lie in less than all features of a singleforegoing disclosed embodiment. Thus, the following claims are herebyincorporated into this Description of Embodiments, with each claimstanding on its own as a separate embodiment of the invention.

Moreover, it will be apparent to those skilled in the art fromconsideration of the specification and practice of the presentdisclosure that various modifications and variations can be made to thedisclosed systems without departing from the scope of the disclosure, asclaimed. Thus, it is intended that the specification and examples beconsidered as exemplary only, with a true scope of the presentdisclosure being indicated by the following claims and theirequivalents.

The invention claimed is:
 1. A system for identifying a plurality ofobjects using capacitive sensing, the system comprising: a sensingarray, wherein: the sensing array includes a capacitive sensor pad; andeach of the plurality of objects includes at least one conductivesurface; and a microcontroller, wherein the microcontroller isconfigured to identify each of the plurality of objects based on atleast one capacitance detected between each of the plurality of objectsand the capacitive sensor pad, wherein each of the plurality of objectsare identified with a ternary code, wherein (i) a first ternary codelevel is associated with a conductive surface including a surface arealarger than a surface area of the capacitive sensor pad and (ii) asecond ternary code level is associated with a conductive surfaceincluding a surface area smaller than the surface area of the capacitivesensor pad.
 2. The system of claim 1, wherein the at least oneconductive surface includes a surface area that is one of (i) largerthan a surface area of the capacitive sensor pad and (ii) smaller thanthe surface area of the capacitive sensor pad.
 3. The system of claim 1,wherein a third ternary code level is associated with a location in theobject without any conductive surfaces.
 4. The system of claim 1,wherein the at least one conductive surface is mounted on an outsidesurface of the object.
 5. The system of claim 1, wherein the at leastone conductive surface is mounted on an inside surface of the object. 6.The system of claim 1, wherein the object is one of: (i) solid and (ii)hollow.
 7. A system for identifying an object using capacitive sensing,the system comprising: a sensing array, wherein: the sensing arrayincludes a plurality of capacitive sensor pads; and the object includesat least one conductive surface; and a microcontroller, wherein themicrocontroller is configured to identify the object based on at leastone capacitance detected between the object and at least one of theplurality of capacitive sensor pads, wherein the object is identifiedwith a ternary code, wherein (i) a first ternary code level isassociated with a conductive surface including a surface area largerthan a surface area of the at least one of the plurality of capacitivesensor pads and (ii) a second ternary code level is associated with aconductive surface including a surface area smaller than the surfacearea of the at least one of the plurality of capacitive sensor pads. 8.The system of claim 7, wherein the at least one conductive surfaceincludes a surface area that is one of (i) larger than a surface area ofthe at least one of the plurality of capacitive sensor pads and (ii)smaller than the surface area of the at least one of the plurality ofcapacitive sensor pads.
 9. The system of claim 7, wherein a thirdternary code level is associated with a location in the object withoutany conductive surfaces.
 10. The system of claim 7, wherein the at leastone conductive surface is mounted on an outside surface of the object.11. The system of claim 7, wherein the at least one conductive surfaceis mounted on an inside surface of the object.
 12. The system of claim7, wherein the object is one of: (i) solid and (ii) hollow.
 13. A methodfor identifying at least one object using capacitive sensing, the methodcomprising: detecting, with a microcontroller, at least one capacitancebetween the at least one object and at least one capacitive sensor padof a sensing array; and identifying, with the microcontroller, the atleast one object based on the detected at least one capacitance, whereinthe at least one object is identified with a ternary code, wherein (i) afirst ternary code level is associated with a conductive surfaceincluding a surface area larger than a surface area of the at least onecapacitive sensor pad and (ii) a second ternary code level is associatedwith a conductive surface including a surface area smaller than thesurface area of the at least one capacitive sensor pad.
 14. The methodof claim 13, wherein the at least one conductive surface includes asurface area that is one of (i) larger than a surface area of the atleast one capacitive sensor pad and (ii) smaller than the surface areaof the at least one capacitive sensor pad.
 15. The method of claim 13,wherein a third ternary code level is associated with a location in theobject without any conductive surfaces.
 16. The method of claim 13,wherein the identifying includes: comparing the detected at least onecapacitance to at least one of an upper limit and a lower limit; anddetermining a ternary code level for the detected at least onecapacitance based on the comparison, wherein: the first ternary codelevel is determined if the detected at least one capacitance is greaterthan the upper limit; the second ternary code level is determined if thedetected at least one capacitance is less than the upper limit butgreater than the lower limit, and a third ternary code level isdetermined if the detected at least one capacitance is less than theupper limit and the lower limit.